From 18a028950bd868c07f9991e6cfb954fa0c967b1f Mon Sep 17 00:00:00 2001
From: Neil Fuller <nfuller@google.com>
Date: Thu, 29 Oct 2020 11:27:11 +0000
Subject: [PATCH] Fix non-deterministic async test

See comments in TimeZoneDetectorCallbackImpl for details.
This is to fix testManageConfiguration.

Bug: 171221358
Bug: 171953500
Test: Ran atest TimeManagerTest with
  location_time_zone_detection_enabled set to 0 and 1
Change-Id: Ife146a5cc9c77a14c45167d70314d248d14445e1
---
 .../TimeZoneDetectorCallbackImpl.java         | 23 +++++++++++++------
 1 file changed, 16 insertions(+), 7 deletions(-)

diff --git a/services/core/java/com/android/server/timezonedetector/TimeZoneDetectorCallbackImpl.java b/services/core/java/com/android/server/timezonedetector/TimeZoneDetectorCallbackImpl.java
index 941be0ede1b9a..1357608ef9d42 100644
--- a/services/core/java/com/android/server/timezonedetector/TimeZoneDetectorCallbackImpl.java
+++ b/services/core/java/com/android/server/timezonedetector/TimeZoneDetectorCallbackImpl.java
@@ -168,7 +168,7 @@ public final class TimeZoneDetectorCallbackImpl implements TimeZoneDetectorStrat
         // that support new types of auto detection on the same hardware.
         if (isAutoDetectionSupported()) {
             final boolean autoDetectionEnabled = configuration.isAutoDetectionEnabled();
-            setAutoDetectionEnabled(autoDetectionEnabled);
+            setAutoDetectionEnabledIfRequired(autoDetectionEnabled);
 
             // Avoid writing the geo detection enabled setting for devices that do not support geo
             // time zone detection: if we wrote it down then we'd set the value explicitly, which
@@ -176,7 +176,7 @@ public final class TimeZoneDetectorCallbackImpl implements TimeZoneDetectorStrat
             // releases that support geo detection on the same hardware.
             if (isGeoDetectionSupported()) {
                 final boolean geoTzDetectionEnabled = configuration.isGeoDetectionEnabled();
-                setGeoDetectionEnabled(userId, geoTzDetectionEnabled);
+                setGeoDetectionEnabledIfRequired(userId, geoTzDetectionEnabled);
             }
         }
     }
@@ -198,8 +198,14 @@ public final class TimeZoneDetectorCallbackImpl implements TimeZoneDetectorStrat
         return Settings.Global.getInt(mCr, Settings.Global.AUTO_TIME_ZONE, 1 /* default */) > 0;
     }
 
-    private void setAutoDetectionEnabled(boolean enabled) {
-        Settings.Global.putInt(mCr, Settings.Global.AUTO_TIME_ZONE, enabled ? 1 : 0);
+    private void setAutoDetectionEnabledIfRequired(boolean enabled) {
+        // This check is racey, but the whole settings update process is racey. This check prevents
+        // a ConfigurationChangeListener callback triggering due to ContentObserver's still
+        // triggering *sometimes* for no-op updates. Because callbacks are async this is necessary
+        // for stable behavior during tests.
+        if (isAutoDetectionEnabled() != enabled) {
+            Settings.Global.putInt(mCr, Settings.Global.AUTO_TIME_ZONE, enabled ? 1 : 0);
+        }
     }
 
     private boolean isLocationEnabled(@UserIdInt int userId) {
@@ -213,9 +219,12 @@ public final class TimeZoneDetectorCallbackImpl implements TimeZoneDetectorStrat
                 (geoDetectionEnabledByDefault ? 1 : 0) /* defaultValue */, userId) != 0;
     }
 
-    private void setGeoDetectionEnabled(@UserIdInt int userId, boolean enabled) {
-        Settings.Secure.putIntForUser(mCr, Settings.Secure.LOCATION_TIME_ZONE_DETECTION_ENABLED,
-                enabled ? 1 : 0, userId);
+    private void setGeoDetectionEnabledIfRequired(@UserIdInt int userId, boolean enabled) {
+        // See comment in setAutoDetectionEnabledIfRequired. http://b/171953500
+        if (isGeoDetectionEnabled(userId) != enabled) {
+            Settings.Secure.putIntForUser(mCr, Settings.Secure.LOCATION_TIME_ZONE_DETECTION_ENABLED,
+                    enabled ? 1 : 0, userId);
+        }
     }
 
     private boolean deviceHasTelephonyNetwork() {